This invention relates to solid state lasers. More particularly, this invention relates to solid state tunable lasers and media therefor.
Solid state lasers which are fluorescent metal ions incorporated into insulating hosts as the active laser medium are well established to have the capability of delivering very high output powers. One disadvantage of these high output solid state lasers is that they can only be operated at a few fixed wavelengths. In many applications, it would be advantageous to have continuously tunable high power coherent light sources. Until recently, such continuously tunable high power coherent light sources could only be achieved in the visible or near infrared by using liquid organic dye lasers. Liquid organic dye lasers however, have none of the practical advantages of compactness, durability, and reliability of solid state devices. One of the first reported broadly tunable, high power solid state lasers was made from certain transition metal ions doped into MgF.sub.2 crystals. These early devices are restricted to the 1 .mu.m to 2 .mu.m band and can only be operated cryogenically.
An advance in this field was made with the announcement of the alexandrite (BeAl.sub.2 O.sub.4 :Cr.sup.3+) laser. The alexandrite laser was demonstrated to have room temperature lasing tunable from 0.70 .mu.m to 0.82 .mu.m. Examples of other broadly tunable Cr.sup.3+ doped laser media include emerald (Be.sub.3 Al.sub.2 Si.sub.6 O.sub.18 :Cr.sup.3+), gadolinium scandium gallate garnet (Gd.sub.3 Sc.sub.2 (GaO.sub.4).sub.3 :Cr.sup.3+) and ordered perovskites (K.sub.2 NaScF.sub.6 :Cr.sup.3+).